The Kinetic Theory of Gases assumes that collisions between gas molecules and the walls of a container are perfectly elastic, gas particles do not have any volume, and there are no repulsive or attractive forces between molecules, but these assumptions is for Ideal Gases.

When the temperature is increases, the kinetic energy of the molecules starts to increase as well. Hence, if we continued to increase the temperature the gas molecules continues to go far apart from the other of its own molecules at very high temperature the molecules of the gases are very and the molecules do not interacts. And at this point the gas starts behaving as the ideal gas.

Hence, we can say that, these assumptions which are made in Kinetic Theory of Gases are true under following conditions only, i.e at very low pressure and at high temperatures, because at low pressures, the volume of the molecules tends to become negligible as compared to the total volume of the gas and at high temperatures the molecules are very far from each other and hence, they do not interact and hence the assumption is applicable at high temperature.